발전소 매립회의 재활용을 위한 물리적 정제 기술 연구

Abstract

Abstract

Beneficiation of coal pond ash by physical separation techniques

Sung-Joo Lee Department of EnergySystems Engineering Graduate School Seoul National University

Coal ash is normally divided by fly ash and bottom ash. In Korea, coal ash was produced about 8.5 million ton in 2010. Almost all of bottom ash produced by coal power plants is disposed in ash ponds. Ash storage areas comprise more than 80% of most coal power plant sites. This disposal method is causing environmental problems and a managerial burden for plant operators. Therefore, this study was undertaken with an objective of developing a multi-stage process to separate coal pond ash into various products. To improve efficiency of the separation, coal ash was separated by sizes and each size fraction was subject to various physical separation processes. The separation processes used were Falcon, flotation, and cyclone (-200 mesh), hindered settling (-16, -12 mesh), tabling (16×200 and 8×16 mesh), and spiral. The results showed that various marketable products, such as aggregate, sand, high-carbon fuel, could be recovered from coal pond ash using the pilot-scale separation system. To develop a multi-stage process, the characteristics of coal pond ash were determined. Various separation processes (hindered settling, spiral, table and Falcon) were evaluated for its effectiveness of separating coal ash in various size ranges. Optimum conditions were identified for each process to reduce the LOI of the coal ash to less than 5%. A pilot-scale unit was constructed with a ultimate goal of development of a full scale commercial plant, converting coal pond ash into aggregate, sand, high-carbon fuel, and very fine inorganic fillers.

Keywords: Coal pond ash, hindered-settling separation, shaking table, flotation, cyclone, Falcon concentration, spiral Student number: 2004-21286